Drive motor for magnetic disks, optical disks, and magneto-optical disks

ABSTRACT

A motor for rotating a magnetic disk, an optical disk, or a magneto-optical disk comprises an armature concentrically secured to a center shaft affixed to the base frame of a disk drive unit. A rotor frame is rotatably supported in a cantilever fashion on a free end of the center shaft by a pair of bearings. The rotor frame is cup-shaped with a depending cylindrical sidewall encircling the outer peripheral surface of the armature. The sidewall includes a disk support that projects outwardly from the sidewall. A permanent magnet secured inside the sidewall interacts with magnetic fields produced by the armature. The cantilever support makes it easier to bring armature leads through a hole in the mounting frame as a part of the manufacturing process. 
     In an alternate embodiment, the center shaft is shortened so that the lower bearing on the shaft rests upon the frame. The cup-shaped rotor is mounted on the bearings with a hub having a depending cylindrical wall mounted on the lower bearing. The frame has an upstanding cylindrical wall encircling the depending cylindrical wall of the hub. The armature is mounted on the outer surface of the upstanding wall so that it encircles the lower bearing. This embodiment has a short axial length which produces a compact motor.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation-in-part application of acopending application entitled "Motor for Driving a Magnetic Disk Havinga Cup-Shaped Rotor", and having Ser. No. 106,626 with a Filing Date ofOct. 6, 1987, now U.S. Pat. No. 4,760,298.

BACKGROUND OF THE INVENTION

This invention relates to a motor for rotating a magnetic disk. Inparticular, it relates to a motor which is used for an application inwhich center portions of a few magnetic disks, each normally formed witha magnetic layer on an aluminum disk, are secured to a rotor frame ofthe motor, and data is recorded on and reproduced from the magneticdisks by magnetic heads disposed near the upper and lower surfaces ofeach magnetic disk. In addition, the motor is suitable for rotatingoptical disks and magneto-optical disks.

FIG. 4 is a longitudinal sectional view showing a conventional structureof a motor for rotating and driving a magnetic disk. In FIG. 4, anupright hollow shaft 2 is formed in the center of a circular mountingframe 1 made by aluminum die casting or the like. A motor 3 has a hollowfixed shaft 4 that is pressed onto the upright hollow shaft 2. Alaminated core 6 of an armature 5 is pressed and secured to an axialcentral portion of the hollow fixed shaft 4. Shoulders 7 are defined onboth ends of the hollow fixed shaft 4 to form small diameter portions 8and 9. Lower portion 8 is slightly longer in the axial direction thanupper portion 9 in order to accommodate two Belleville springs 10 thatare inserted onto the lower small diameter portion 8. Springs 10 exertforce on a lower roller bearing 11 that is inserted on portion 8. Anupper roller bearing 14 is pressed onto portion 9 and confined betweenthe upper portion 9 and an end plate 13 of a rotor frame 12, so that theframe 12 may be rotatably supported by bearings 11 and 14 on the hollowfixed shaft 4. The rotor frame 12 is in the shape of a cup. An axialcylindrical side wall 54 covers an outer peripheral surface of thearmature 5, and an outer end of the side wall 54 serves as a magneticdisk support 15 which is projected outwardly perpendicular to the motoraxis. Support 15 is opposed to the mounting frame 1, thereby leaving asmall clearance. An annular recess 16 formed at an inner corner of themagnetic disk support 15 is provided for a good contact between themagnetic disk support 15 and a magnetic disk placed thereon.

An annular permanent magnet 17 having the desired number of poles ispressed and secured into the cylindrical side wall 54, after which anend plate 19 is pressed and secured to the roller bearing 11. The rollerbearing 11 is then pressed and secured to shaft 4, and the end plate 19is attached to the end of the side wall 54 to form a rotor 20. The rotor20, the armature 5 and the hollow fixed shaft 4 comprise the motor 3. Aset of lead wires 22 of an armature coil 21 is drawn out of a hole 23provided in the hollow fixed shaft 4 and pulled into the hollow portionof shaft 4. The wires are then pulled outside of the motor through thehollow portion of the hollow shaft 2.

FIG. 5 is a sectional view of a portion of the conventional magneticdisk drive motor having the structure described above. In FIG. 5, centerholes of the magnetic disks 24 are fitted on the side wall 54 of therotor frame 12, placed on the disk receiving base 15 in a predeterminedspaced relation with spacers 25, and secured by means of a pressureplate 26 and a screw 27. In order to maintain a predetermined smallclearance between the surface of each magnetic disk 24 and a radiallymoving magnetic head 28, vibrations resulting from rotation of the sidewall 54 and magnetic external disk support 15 have to be minimized.Further, the width of vertical variation of the rotating disk support 15should be 0.005 mm or less.

However, in the aforementioned conventional construction, it is verydifficult to make the lateral hole 23 through which the lead wires 22pass in the hollow fixed shaft 4, and the number of parts is large,which increases the cost of the motor.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a motor having a cupshaped rotor, suitable for driving a magnetic disk, an optical disk, anda magnetooptical disk, which is designed so that the armature is securedto a mounting frame and a lead wire of the armature coil may be drawnout of a hole formed in the mounting frame, thereby reducing the cost ofconstructing the motor.

In one embodiment of the present invention, an armature is securedconcentrically to a center shaft secured integrally on a mounting frame.A rotor frame having a cylindrical side wall of uniform outside diameteris rotatably supported in a cantilever fashion on a free end of thecenter shaft by means of a pair of ball bearings which encircle theouter peripheral surface of the armature. A disk support projects fromsaid side wall, and a permanent magnet is secured inside the side walland opposed to the outer peripheral surface of the armature, leaving anair gap.

In this embodiment of the invention, the rotor frame is supportedrotatably and in a cantilever fashion on the center shaft to which issecured the armature by means of a pair of ball bearings. Therefore,even if the side wall of the rotor frame is extended so as to cover theouter periphery of the armature, no side run-out relative to thearmature occurs and the rotor rotates freely. Accordingly, a diskmounted on the rotor frame may be rotated accurately without side runoutor the like. In addition, since the motor is not provided with an endplate on the side of the mounting frame to encircle the armature, thereare fewer parts, and the coil lead wire may be drawn outside the framethrough a hole formed in the mounting frame, thus materially simplifyingthe construction of the whole motor.

According to a second embodiment of the present invention, a cup-shapedrotor includes an armature secured concentrically to a center axial pipesecured to a mounting frame. A rotor frame having a cylindrical sidewall of uniform outside diameter is rotatably supported in a cantileverfashion on a center shaft pressed and secured to a center hole of a freeend of the center axial pipe by means of a pair of ball bearings. A disksupport is secured to the side wall, and a permanent magnet is securedinside the side wall and opposed to the outer peripheral surface of thearmature, leaving an air gap.

In this embodiment of the invention, the structure is similar to that ofthe first embodiment except that the rotor center shaft is pressed onand secured to the central axial pipe on the mounting frame. If thepressed length is great and the pressing accuracy is good, thisembodiment has the same advantages as the first embodiment. If themounting frame and the center axial pipe are integrally formed byaluminum die casting, the manufacturing cost is less.

In the disk drive motor of the prior art, as shown in FIG. 4, and in theembodiments of the invention which have been defined hereinabove, thearmature is secured concentrically to a center shaft which is securedintegrally on a mounting frame. That is to say, the motor must bemounted by means of the mounting frame onto the base frame on the diskdrive apparatus. It is within the scope of the present invention toeliminate the mounting frame and provide a disk drive motor wherein thecenter shaft is secured integrally on the base frame of the disk driveapparatus itself.

In such an embodiment, the motor has a frame having a planar bottommember with upstanding sidewalls. An upstanding shaft integral on theplanar bottom member is spaced from the side walls a distance greaterthan the radius of the magnetic or optical disks. An aperture isprovided in the planar bottom member adjacent the upstanding shaft. Acore is mounted on the upstanding shaft proximate to the planar bottommember and a winding is mounted on the core to provide an armature whichis energizable by receiving electrical energy from lead wires passing tothe armature through the aperture. A pair of spaced apart bearings aremounted on the upstanding shaft above the armature and a cup-shapedrotor is mounted on the bearings. This allows the rotor to rotate aboutthe upstanding shaft and the armature. The rotor has a cylindrical openbottom encompassing the armature and it includes a disk support meansfor mounting disks on the rotor in a plane perpendicular to the axis ofthe upstanding shaft. A plurality of permanent magnets is mounted withinthe cup-shaped rotor proximate to and spaced from the armature inmagnetic engagement, whereby the rotor rotates about the upstandingshaft and the armature when the armature is electrically energized.

In a further embodiment of the present invention the disk drive motorhas an axial length which is highly foreshortened so that it can be usedwhere space limitations require the use of a compact motor. Thisinvention comprehends a motor having a frame with a planar bottommember, an upstanding shaft on the planar bottom member, and an aperturein the planar bottom member. Upper and lower spaced apart bearings aremounted on the upstanding shaft proximate the planar bottom member, anda cup-shaped rotor having a central hub is mounted on the bearings toallow the rotor to rotate about the upstanding shaft. The central hubincludes a depending cylindrical wall portion which is mounted on thelower bearing. An upstanding cylindrical wall on the planar member isspaced from and encircles the depending cylindrical wall portion of therotor central hub, and a core is mounted on the outside surface of thisupstanding cylindrical wall. A winding is mounted on the core to providean armature which is energizable by receiving electrical energy fromlead wires passing to the armature through the aperture. The cup-shapedrotor also has a depending outer cylindrical wall which is spaced fromand encircles the armature. A plurality of permanent magnets is mountedon the inside surface of this rotor outer cylindrical wall proximate toand spaced from the armature in magnetic engagement, whereby the rotorrotates about the upstanding shaft and the armature when the armature isenergized.

A clearer understanding of the present invention will be obtained fromthe disclosure which follows when read in light of the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of one embodiment of the presentinvention.

FIG. 2 is a sectional view taken on line II--II of FIG. 1.

FIG. 3 is a longitudinal sectional view of an alternate embodiment ofthe invention.

FIG. 4 is a longitudinal sectional view of a motor of the prior art.

FIG. 5 is a partial sectional elevational view of a rotor of the priorart with magnetic disks mounted thereon.

FIG. 6 is a longitudinal sectional view of a further alternateembodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a portion of thestructure FIG. 6 wherein an alternate form of the motor shaft is shown.

FIG. 8 is an enlarged longitudinal sectional view of a portion of FIG. 7showing means for positioning the motor bearings in greater detail.

FIG. 9 is an enlarged longitudinal sectional view similar to FIG. 8, butshowing alternate means for positioning the motor bearings.

FIGS. 10A, 10B and 10C are plan views of alternate embodiments of thebearing spacer for the inventive motor.

FIG. 11 is a longitudinal sectional view showing a portion of thestructure of FIG. 6 wherein another alternate form of the motor shaft isshown.

FIG. 12 is a longitudinal sectional view showing a portion of thestructure of FIG. 6 wherein a further alternate form of the motor shaftis shown.

FIG. 13 is a repeat of FIG. 12, but showing an embodiment wherein theinner bearing races are formed in the surface of the motor shaft.

FIG. 14 is an enlarged longitudinal sectional view of a portion of FIG.13, showing the bearings in greater detail.

FIG. 15 is a longitudinal sectional view of a still further embodimentof the present invention wherein the motor has a very short axiallength.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a longitudinal sectional view of an embodiment of theinvention in which parts which are the same as those shown in FIG. 4 areindicated by the same reference numerals.

In FIG. 1, a circular mounting frame 1a has a center shaft 31 in thecenter of a dished portion 30, and projecting outwardly from the dishedportion 30 is a flange 29. The frame 1a is preferably formed of steel. Alaminated core 6 of an armature 5 is pressed on and secured to amiddle-diameter portion 33 which abuts a lower large-diameter portion 32at the base of the center shaft 31. The core 6 is placed in contact withthe large-diameter portion 32, and lead wires 22 connected to anarmature coil 21 through a printed-circuit board 34 are taken through ahole 35 formed in the dished portion 30.

The center shaft 31 is formed at its free end with a small-diameterportion 36, on which are pressed and glued or cemented the inner seatsof a pair of ball bearings 37 and 38. The inner seat of the bearing 38is brought into contact with the middle-diameter portion 33, leaving asmall clearance between the bearings 37 and 38.

A steel rotor frame 12a constituting a rotor 20a is formed into a cupshape. An outer seat of the bearing 38 is pressed into and glued orcemented to a center hole 40 of a thick-walled portion 39 correspondingto the bottom of the cup. The outer-seat of the bearing 37 is fittedloosely in the center hole 40. Two stacked Belleville springs 41 arecompressed and interposed with appropriate pre-loading between the outerseats of the bearings 37 and 38 so that the outer seat of the bearing 37is moved slightly in an axial direction to remove play in both axial andradial directions of the bearings 37 and 38. A cylindrical side wall 43,which is a uniform diameter extension of the thick-wall portion 39, isextended into a recess 44 of the dished portion 30 covering the outerperipheral surface of the core 6. An annular permanent magnet 17 isfitted on the inner surface of the side wall 43 in a face-to-facerelation with an iron core 6 leaving an air gap. A magnetic disk support15 is provided as a projection on the upper surface of the side wall 43adjacent to the outer surface of the flange 29. The magnetic disksupport 15 has an upper surface 45 perpendicular to the center shaft 31.An annular recess 16 is formed at the inner end of the surface 45.

The armature 5 has a coil 21 wound within a slot 46 provided in the core6, as shown in FIG. 2, that can be energized so as to generate rotatingfields that interact with those of the permanent magnet 17 to producetorque, causing the rotor 20a to rotate in the same direction as that ofthe rotating field. The rotor 20ais closely supported on the centershaft 31 by the bearings 37 and 38, and the thick-wall portion 39 firmlysupports rotational parts such as the side wall 43 extending therefrom,the permanent magnet 17, the disk support 15 and the magnetic disk fixedon the support 15, thus providing an accurate rotation without rotationrunout.

FIG. 3 is a longitudinal sectional view of an alternate embodiment ofthe invention, in which parts indicated by the same reference numbers asthose used in FIGS. 1 and 4 have the same construction as those showntherein, and parts different in construction from those shown in FIG. 4are indicated by reference numerals with a letter "b" attached thereto.A circular dish-like mounting fame 1b is formed integral with a centeraxial pipe 2b projected in the central portion by aluminum die casting.A laminated core 6 of an armature 5 is placed in contact with alarge-diameter portion 32b and is pressed and secured to a middlediameter portion 33b that abuts to a lower large-diameter portion 32b atthe base of the center axial pipe 2b. A mechanism for bringing out leadwires of an armature coil 21 is similar to that shown in FIG. 1.

A small-diameter portion 48 of a steel center shaft 47 is pressed andsecured into a center hole formed in a free end of the center axial pipe2b, and a large diameter portion 49 is brought into contact with the endof the center axial pipe 2b. The small-diameter portion 48 is longenough so that the small-diameter portion 48 maintains alignment ofcenter shaft 47 with the center axial pipe 2b. The wall thickness of thecenter axial pipe 2b is great enough to withstand the force used topress fit the small diameter portion 48 and also to minimize rotationalvibrations of the rotor 20a.

The structure of the rotor 20a mounted on the large-diameter portion 49is exactly the same as that shown in FIG. 1, and the ball bearings 37and 38 are mounted in a manner similar to that shown in FIG. 1.

Although they are not shown in FIGS. 1 and 3, Hall elements to detect arotational position of the permanent magnet 17 are mounted on themounting frames 1a and 1b, and a detection signal therefrom controls theelectrical energy supplied to the armature coil 21 to generate arotating field.

As described above, according to the present invention, two ballbearings are provided on one side of the rotor to support the rotor 20ain a cantilever fashion. Therefore, the lead wires of the armature coilmay be brought out of the hole 35 of the circular mounting frame 1bdirectly without passing through the center shaft, thus making assemblyof the motor simple as compared to the prior art. Also, an end plate formounting one bearing can be eliminated to greatly reduce the cost.

As noted hereinabove, the mounting frames 1a of FIG. 1 and 1b of FIG. 3are intended to be secured to the base frame of the disk drive apparatusunit. In the embodiments which are presented in FIGS. 6-14, the mountingframes 1a and 1b are eliminated and the disk drive motor is mounted onan upstanding shaft which is an integral part of the base frame of thedisk drive unit itself. Thus, the whole structure may be simplified, andthe assembly work may be easier, since the motor may be assembleddirectly within the disk drive apparatus itself.

Referring now to FIG. 6, there is shown the basic motor which isdisclosed in the embodiment of FIG. 1. This motor has a frame 1c whichis the base frame of the entire disk drive apparatus unit. Frame 1c hasa planar bottom member 66, side walls 67, and a cover plate 68. In thisstructure of the disk drive unit, the center shaft 31 is shown havingthe same construction as disclosed in FIG. 1. Shaft 31 has a smalldiameter upper portion 36, a middle diameter center portion 33, and alarge diameter upper portion 32. The center shaft 31 is integrallymounted on the planar bottom member 66. The planar bottom member alsohas an aperture 71 through which lead wires 22 are passed to thearmature 5. The planar bottom member additionally has a circular rib 69which forms a dish-like pocket around the center shaft 31.

Upper portion 36 of the center shaft 31 has a lower bearing 61 and anupper bearing 56 mounted thereon. The bearings are separated byBelleville springs 10. The cup-shaped rotor 20a is mounted on thebearings 56, 61 and is thereby rotatable on the center shaft. Projection15 from the cup-shaped rotor frame 12a has a plurality of magnetic disks24 mounted thereon. These magnetic disks are separated by the spacers 25and they are read by the magnetic heads 28. Permanent magnets 17 aremounted on the inside surface of the rotor frame 12a in a positionopposite to the armature 5 and spaced therefrom. Also mounted on therotor frame 12a is a pressure plate or holddown plate 26 which securesthe magnetic disks 24 and the spacers 25 on the cup shaped rotor. Theholddown plate 26 is secured to the rotor frame 12a by means ofplurality of screws 27, only one of which is shown. A cap 77 covers thecenter shaft 31 and the bearings in order to protect the bearings fromatmospheric dust.

FIG. 7 shows a further embodiment of the apparatus of FIG. 6. Elementswhich have been shown in FIG. 6 are also shown in FIG. 7. The differencebetween these two embodiments is that the embodiment of FIG. 7 has acenter shaft 72 mounted on the planar member 66 which has a constantdiameter. The armature 5, the lower bearing 61 and the upper bearing 56are mounted on this constant diameter shaft and are separatedappropriately by means of spacers. A bottom spacer 73 resting upon theupper surface of the planar member 66 provides the support of thearmature 5. A spacer element 74 is mounted on the armature 5 and in turnsupports the lower bearing 61. A spacer 75 is mounted on the top of thelower bearing 61 and in turn supports the upper bearing 56.

FIG. 8 is an enlargement of a portion of FIG. 7 wherein the bearings areshown more clearly. FIG. 8 shows the upper portion of the center spacers74 supporting the inner race 62 of the lower bearing 61. The outer race63 is mounted on the inner surface of the rotor frame 12a and the innerrace 62 is mounted on the center shaft 72. These races are mounted onthe center shaft and the rotor frame by a press fit or they may beadhesively secured. An epoxy cement is suitable for adhesively securingthe races of the ball bearing. The upper ball bearing is supported by aspacer 75 confined between the lower ball bearing 61 and the upper ballbearing 56. It will be seen in FIG. 8 that the lower ball bearing 61 hasits inner face 62 elevated slightly above the outer race 63. In asimilar manner the upper bearing 56 has its inner face 57 depressedslightly below the outer race 58. This difference in the alignment ofthe inner and outer races causes the bearing balls 59 of upper bearing56 and the bearing balls 64 of the lower bearing 61 to be more tightlyheld within the races. By thus reducing the play in the bearings, thispreloading of the bearings minimizes vibration of the rotor when themotor is running.

FIG. 9 illustrates an alternate embodiments wherein the spacer 75 hasbeen eliminated. In this embodiment a projection or stepped portion 76on the inner surface of rotor frame 12a is used to separate the bearings56 and 61.

FIG. 9 also illustrates the means by which the bearings may be preloadedin order to minimize vibration. The bearings may be adhesively securedon the rotor surface 12a and on the center shaft 72. An epoxy resinadhesive is suitable. When the bearings have been placed in position, anexternal force F is applied to the inner race 57 of the upper bearing tomisalign the inner race 57 from the outer race 58. This force is heldwhile the adhesive cures to secure the races on the surface of the shaft72 and the rotor 12a. When the adhesive has set, the external force isreleased and the permanent misalignment of the races has imparted apreloading to the upper bearing. Similarly, while external force F isbeing applied to the upper bearing 56, an internal reaction force isbeing responsively applied to the lower bearing 61 by the middle spacer74 to thereby cause a permanent misalignment of the inner race 62 fromthe outer race 63 in the lower bearing. This provides the preloading ofthe lower bearing.

The spacers 73, 74 and 75 are annular rings but they may be segmentedannular rings. This concept is illustrated in FIGS. 10A, 10B, and 10Cwherein the spacer 75 is shown for purposes of illustration. In FIG.10A, spacer 75 is shown to have four segments 75a, each defining aquarter of a circle. In FIG. 10B, the spacer 75 is shown as having twosegments 75b which are a half circle having a C-shape. In FIG. 10C, thespacer 75 is shown as having a single segment 75c which has a C-shape.This C-shaped segment has a diameter that is slightly larger than thediameter of the inside surface of the cup-shaped rotor frame 12a, sothat when the spacer 75 is inserted it will press tightly against theinner surface of the rotor frame. In a similar manner, the spacers 73and 74 may be segmented.

FIG. 11 shows another embodiment of the motor structure of FIG. 6. Inthis embodiment, the shaft has a lower portion 79 which contains acentral bore 80. The shaft also includes a supporting post 81 which ispress fit into the central bore 80, and the upper and lower bearings 56and 61 are mounted on this supporting post. This embodiment also showsthat the rotor frame 12b has an inward step 83 which holds the outerrace of the lower bearing 61.

FIG. 12 illustrates an alternate embodiment of FIG. 11. In thisembodiment the supporting post 85 has a small diameter lower portion 86and a large diameter upper portion 87. The large diameter portion 87rests upon the upper surface or end of the lower shaft portion 79 andthe small diameter portion 86 is press fit within the bore 80.

FIG. 13 shows an alternate embodiment of the motor of FIG. 12. In thisembodiment, the inner race of the upper bearing 56 and the inner race ofthe lower bearing 61 have been eliminated. The bearing balls aresupported in recesses which are contained in the surface of the supportpost upper portion 87. This is more clearly shown in FIG. 14. Thebearing balls 59 of the upper bearing 56 are contained within an upperrecess 88 in the large diameter portion 87 of the support post 85.Similarly, the bearing balls 64 of the lower bearing 61 are supported inrecess 89 in the outer surface of the large diameter portion 87.Recesses 88, 89 are suitably misaligned in relation to outer races 58,63 in order to preload the bearings.

FIG. 15 is a longitudinal sectional view of another embodiment of thedisk drive motor of the present invention wherein the motor has a veryshort axial length in order to provide for a compact structure. Themotor has a bottom frame 1d which has a planar bottom member 90. Theplanar bottom member 90 contains an aperture 71 through which the leadwires 22 may pass to the armature 5. The shaft of the motor has a lowerportion 91 having a central bore 92. The shaft also includes asupporting post 93 which is press fit or adhesively secured within thecentral bore 92. Lower ball bearing 61 and upper ball bearing 56 aresecured to the surface of the supporting post 93. Lower bearing 61 sitsupon the end of the shaft lower portion 91 and upper bearing 56 sitsupon the spacer 75.

A cup-shaped rotor 20c is mounted on the outer races of the bearings 56and 61 by means of a hub 95 which includes a depending cylindrical wallportion 96. The rotor also has a depending outer cylindrical wall 97. Anupstanding cylindrical wall 94 is provided on the planar bottom member90. This wall 94 is spaced from and encircles the depending cylindricalwall portion 96 of the rotor hub. The armature 5 is mounted on the outersurface of the upstanding cylindrical wall 94. Depending outercylindrical wall 97 of the rotor is spaced from and encircles thearmature 5. A plurality of permanent magnets is mounted on the insidesurface of the outer cylindrical wall 97. The magnets are proximate toand spaced from the armature in magnetic engagement, whereby the rotor20c rotates about the upstanding shaft and the armature when thearmature is electrically energized. Cup-shaped rotor 20c also has asurface 98 which is perpendicular to the motor axis. Surface 98 isadapted to hold a magnetic disk, an optical disk, or a magneto-opticaldisk. Rotor 20c also has a plurality of threaded bores 99 for receivingscrews 27 (not shown) for securing the holddown plate 26 (not shown)which secures a magnetic disk on surface 98.

In light of the foregoing disclosure, further alternative embodiments ofthe inventive disk drive motor will undoubtedly suggest themselves tothose skilled in the art. It is thus intended that the disclosure betaken as illustrative only, and that it not be construed in any limitingsense. Modifications and variations may be resorted to without departingfrom the spirit and t he scope of this invention, and such modificationsand variations are considered to be within the purview and the scope ofthe appended claims.

What is claimed is: .[.
 1. A motor, suitable for driving a magneticdisk, an optical disk, or a magneto-optical disk, which comprises:a. aframe having a planar bottom member; b. an upstanding shaft on saidplanar bottom member, said upstanding shaft having a large diameterlower portion, an intermediate diameter middle portion and a smalldiameter upper portion; c. an aperture in said planar bottom member; d.a core mounted on said upstanding shaft on said middle portion andseated against said lower portion proximate said planar bottom member;e. an armature wound on said core and energizable by receivingelectrical energy from wires passing to said armature through saidaperture; f. a pair of spaced apart bearings mounted on said upstandingshaft on said upper portion above said armature; g. a cup shaped rotormounted on said bearings to allow said rotor to rotate about saidupstanding shaft and armature, said rotor having a cylindrical openbottom encompassing said armature, and said rotor including disk supportmeans for mounting a disk on said rotor in a plane perpendicular to theaxis of said upstanding shaft; and h. a plurality of permanent magnetsmounted within said cup shaped rotor proximate to and spaced from saidarmature in magnetic engagement, whereby said rotor rotates about theupstanding shaft and armature when said armature is energized..]. .[. 2.A motor according to claim 1 wherein said bearings are spaced apart byspring elements..]. .[.3. A motor according to claim 2 wherein saidspring elements are Belleville springs..]. .[.4. A motor according toclaim 1 wherein said bearings are spaced apart by an annular spacer..]..[.5. A motor according to claim 4 wherein said annular spacer is anannular ring..]. .[.6. A motor according to claim 5 wherein said annularring comprises an annular segment..]. .[.7. A motor according to claim 5wherein said annular ring comprises a plurality of annular segments..]..[.8. A motor according to claim 4 wherein said annular spacer comprisesan annular projection on the inside surface of said cup shaped rotor..]..[.9. A motor according to claim 11 wherein said disk support meanscomprises an annular projection on the outside of said open bottom ofthe cup shaped rotor, and said annular projection has an upper surfacein a plane perpendicular to the axis of said upstanding shaft..]. .[.10.A motor according to claim 9 wherein said rotor has a cylindrical outersurface above said annular projection, whereby a plurality of disks maybe mounted on said rotor..].
 11. A motor, suitable for driving amagnetic disk, an optical disk, or a magneto-optical disk, whichcomprises:a. a frame having a planar bottom member; b. an upstandingshaft on said planar bottom member, said upstanding shaft including alower portion having a central bore and a post having upper and lowerportions, said post lower portion being secured within said centralbore, and said post upper portion having an outer surface having twospaced apart circumferential recesses for providing bearing inner races;c. an apertures in said planar bottom member; d. upper and lower spacedapart bearings mounted on said post upper portion and in said recessesproximate said planar bottom member; e. a cup shaped rotor having acentral hub mounted on said bearings to allow said rotor to rotate aboutsaid upstanding shaft, said central hub including a dependingcylindrical wall portion mounted on said lower bearing; f. an upstandingcylindrical wall on said planar bottom member, spaced from andencircling said depending cylindrical wall portion of said rotor centralhub; g. a core mounted on the outside surface of said upstandingcylindrical wall; h. an armature wound on said core and energizable byreceiving electrical energy from wires passing to said armature throughsaid aperture; i. a depending outer cylindrical wall on said rotor,spaced from and encircling said armature; and, j. .[.a plurality of.]..Iadd.at least one .Iaddend.permanent .[.magnets.]. .Iadd.magnet.Iaddend.mounted on the inside surface of said rotor outer cylindricalwall proximate to and spaced from said armature in magnetic engagement,whereby said rotor rotates about said upstanding shaft and armature whensaid armature is energized.
 12. A motor, suitable for driving a magneticdisk, an optical disk, or a magneto-optical disk, which comprises:a. aframe having a planar bottom member; b. an upstanding shaft on saidplanar bottom member, said upstanding shaft including a lower portionhaving a central bore and a post having upper and lower portions, andsaid post lower portion being secured within said central bore; c. anaperture in said planar bottom member; d. a core mounted on .Iadd.theoutside surface of .Iaddend.said upstanding shaft lower portionproximate said planar bottom member; e. an armature wound on said coreand energizable by receiving electrical energy from wires passing tosaid armature through said aperture; f. a pair of spaced apart bearingsmounted on said post upper portion .Iadd.at least partially.Iaddend.above said armature; g. a cup shaped rotor mounted on saidbearings to allow said rotor to rotate about said upstanding shaft andarmature, said rotor having a cylindrical open bottom encompassing saidarmature, and said rotor including disk support means for mounting adisk on said rotor in a plane perpendicular to the axis of saidupstanding shaft; and h. .[.a plurality of.]. .Iadd.at least one.Iaddend.permanent .[.magnets.]. .Iadd.magnet .Iaddend.mounted withinsaid cup shaped rotor proximate to and spaced from said armature inmagnetic engagement, whereby said rotor rotates about the upstandingshaft and armature when said armature is energized.
 13. A motoraccording to claim 12 wherein said post upper portion has a diametergreater than said post lower portion and said post upper portion isseated against the end of said shaft lower portion.
 14. A motoraccording to claim 12 wherein said post upper portion has an outersurface having recesses providing the inner races of said bearings..[.15. A motor according to claim 1 wherein said aperture is locatedproximate said upstanding shaft..]. .[.16. A motor according to claim 1wherein said permanent magnets are disposed angularly on an insidesurface of said rotor so as to present alternate north and south polesin magnetic engagement with said armature..]. .[.17. A motor accordingto claim 1 including at least one side wall in the shape of a segment ofa hollow cylinder..]. .[.18. A motor, suitable for driving a magneticdisk, an optical disk, or a magneto-optical disk, which comprises:a. aframe having a planar bottom member; b. an upstanding shaft on saidplanar bottom member, said upstanding shaft including a lower portionhaving a central bore and a post having upper and lower portions, saidpost upper portion having a diameter greater than said post lowerportion, said post lower portion being secured within said central bore,and said post upper portion being seated against the end of said shaftlower portion; c. an aperture in said planar bottom member; d. upper andlower spaced apart bearings mounted on said post upper portion proximatesaid planar bottom member; e. a cup shaped rotor having a central hubmounted on said bearings to allow said rotor to rotate about saidupstanding shaft, said central hub including a depending cylindricalwall portion mounted on said lower bearing; f. an upstanding cylindricalwall on said planar bottom member, spaced from and encircling saiddepending cylindrical wall portion of said rotor central hub; g. a coremounted on the outside surface of said upstanding cylindrical wall; h.an armature wound on said core and energizable by receiving electricalenergy from wires passing to said armature through said aperture; i. adepending outer cylindrical wall on said rotor, spaced from andencircling said armature; and, j. a plurality of permanent magnetsmounted on the inside surface of said rotor outer cylindrical wallproximate to and spaced from said armature in magnetic engagement,whereby said rotor rotates about said upstanding shaft and armature whensaid armature is energized..]. .[.19. A motor according to claim 18wherein said bearings are spaced apart by spring elements..]. .[.20. Amotor according to claim 19 wherein said spring elements are Bellevillesprings..]. .[.21. A motor according to claim 18 wherein said bearingsare spaced apart by an annular spacer..]. .[.22. A motor according toclaim 21 wherein said annular spacer is an annular ring..]. .[.23. Amotor according to claim 22 wherein said annular ring comprises anannular segment..]. .[.24. A motor according to claim 22 wherein saidannular ring comprises a plurality of annular segments..]. .[.25. Amotor according to claim 21 wherein said annular spacer comprises anannular projection on the inside surface of said rotor central hub..]..[.26. A motor according to claim 18 wherein said cup shaped rotorincludes disk support means for mounting a disk on said rotor in a planeperpendicular to the axis of said upstanding shaft..]. .[.27. A motoraccording to claim 1 wherein said aperture is located proximate saidarmature..]. .[.28. The motor of claim 1 wherein said permanent magnetsare disposed angularly on the inside surface of said rotor so as topresent alternate north and south poles in magnetic engagement with saidarmature..].
 29. A motor according to claim 11 wherein said cup shapedrotor includes disk support means for mounting a disk on said rotor in aplane perpendicular to the axis of said upstanding shaft.
 30. A motoraccording to claim 11 wherein said aperture is located proximate saidarmature. .[.31. The motor of claim 11 wherein said permanent magnetsare disposed angularly on the inside surface of said rotor so as topresent alternate north and south poles in magnetic engagement with saidarmature..].
 32. A motor according to claim 12 wherein said bearings arespaced apart by spring elements.
 33. A motor according to claim 32wherein said spring elements are Belleville springs.
 34. A motoraccording to claim 12 wherein said bearings are spaced apart by anannular spacer.
 35. A motor according to claim 34 wherein said annularspacer is an annular ring.
 36. A motor according to claim 35 whereinsaid annular ring comprises an annular segment.
 37. A motor according toclaim 35 wherein said annular ring comprises a plurality of annularsegments.
 38. A motor according to claim 34 wherein said annular spacercomprises an annular projection on the inside surface of said cup shapedrotor.
 39. A motor according to claim 12 wherein said disk support meanscomprises an annular projection on the outside of said open bottom ofthe cup shaped rotor, and said annular projection has an upper surfacein a plane perpendicular to the axis of said upstanding shaft.
 40. Amotor according to claim 39 wherein said rotor has a cylindrical outersurface above said annular projection, whereby a plurality of disks maybe mounted on said rotor. A motor according to claim 12 wherein saidaperture is located proximate said upstanding shaft.
 42. A motoraccording to claim 12 wherein .[.said.]. .Iadd.a plurality of.Iaddend.permanent magnets are disposed angularly on an inside surfaceof said rotor so as to present alternate north and south poles inmagnetic engagement with said armature.
 43. A motor according to claim12 including at least one side wall in the shape of a segment of ahollow cylinder.
 44. A motor according to claim 11 wherein said bearingsare spaced apart by spring elements.
 45. A motor according to claim 44wherein said spring elements are Belleville springs.
 6. A motoraccording to claim 11 wherein said bearings are spaced apart by anannular spacer.
 47. A motor according to claim 46 wherein said annularspacer is an annular ring.
 48. A motor according to claim 47 whereinsaid annular ring comprises an annular segment.
 49. A motor according toclaim 47 wherein said annular ring comprises a plurality of annularsegments. A motor according to claim 46 wherein said annular spacercomprises an annular projection on the inside surface of said rotorcentral hub. .Iadd.51. A motor, suitable for driving a magnetic disk, anoptical disk, or a magneto-optical disk which comprises:a. a framehaving a planar bottom member; b. an upstanding shaft including a lowerportion mounted to said planar bottom member and an upper portionprojecting upwardly therefrom; c. an aperture in said planar bottommember; d. upper and lower spaced apart bearings mounted on said shaftupper portion proximate said planar bottom member; e. a cup shaped rotorhaving a central hub mounted on said bearing to allow said rotor torotate about said upstanding shaft, said central hub including adepending cylindrical wall portion mounted on said lower bearing anddisk support means for mounting a disk on said rotor in a planeperpendicular to the axis of the upstanding shaft; f. an upstandingcylindrical wall on said planar bottom member, spaced from andencircling said depending cylindrical wall portion of said rotor centralhub; g. a core mounted on the outside surface of said upstandingcylindrical wall; h. an armature wound on said core and energizable byreceiving electrical energy from wires passing to said armature throughsaid aperture; i. a depending outer cylindrical wall on said rotor,spaced from and encircling said armature; j. the inner diameter of saiddisk support means being greater than the outer diameter of thedepending cylindrical wall portion and less than the outer diameter ofthe depending outer cylindrical wall; k. at least one permanent magnetmounted on the inside surface of said rotor outer cylindrical wall andthe armature are positioned at a level lower than the disk support meansand said permanent magnet being proximate to and spaced from saidarmature in magnetic engagement, whereby said rotor rotates about saidupstanding shaft and armature when said armature is energized. .Iaddend..Iadd.52. A motor according to claim 51 wherein the planar bottom memberis provided with a bore, and wherein the lower portion of the shaft issecured therewithin. .Iaddend. .Iadd.53. A motor according to claim 52wherein said planar bottom member is provided with an annular axiallyupwardly projecting portion about said bore, and wherein said upstandingcylindrical wall projects upwardly therefrom. .Iaddend. .Iadd.54. Amotor according to claim 51 wherein the armature and bearings are atleast in partial overlapping axial relationship. .Iaddend.